Add Mitsubishi Electric MSY-GE series (cooling-only splits) — device code 1141

[messelink]

Add Mitsubishi Electric MSY-GE series (cooling-only splits)

Adds a climate device file for the Mitsubishi Electric MSY-GE series —
MSY-GE13VA, MSY-GE15VA, MSY-GE15VE (cooling-only wall splits, common in
SG/AU). Stock support for these is thin; the closest existing codes only covered
cool / fan-auto / a narrow temp band.

• Controller / encoding: Broadlink / Base64
• Modes: cool, dry, fan_only, auto (the remote's "I FEEL" auto-select)
• Fan: auto, quiet, low, medium, high, max
• Swing/vane: auto, highest, high, middle, low, lowest, swing
• Temperature: full 16–31 °C, 1° steps
• 2688 commands + off (~2.1 MB)
• Filed as device code 1141 (first free slot after the existing Mitsubishi
  Electric block 1120–1139); renumber if you'd prefer a different slot. Docs
  table (docs/CLIMATE.md) updated to match.

How the codes were produced (provenance)

Rather than learning a handful of buttons, the full remote IR protocol was
reverse-engineered and verified, then every command was generated from the
confirmed frame structure (18-byte Mitsubishi Electric frame, sent twice):

B5 power | B6 mode (cool 0x18 / dry 0x10 / fan_only 0x38 / auto 0x00) |
B7 temp-16 | B8 mode-linked | B9 = vane(high) | fan(low) | B17 checksum

• cool + temperatures decode byte-identical to codes hand-learned from the
  physical remote, and the temperature field follows B7 = temp − 16 exactly.
• fan speeds, modes, and vane positions were confirmed by transmitting and
  observing the unit.
• Cross-checked against ESPHome heatpumpir's mitsubishi_msy constants.
• Each generated code is round-trip checked: Broadlink-decode →
  Mitsubishi frame must equal the source frame.

Honest scope / caveats

• Functionally verified on a Tuya Zigbee IR blaster (Zigbee2MQTT) — the codes
  are the remote's exact timings, so they should work on any IR controller
  (Broadlink included), but I have not tested on Broadlink hardware; please
  confirm if you can.
• The full swing/vane matrix (5 positions + swing + auto) is included, which
  is what brings the file to ~2.1 MB / 2688 codes. If you'd prefer a slimmer file
  (cool-only is the common case here), the swing axis can be dropped — let me know.

🤖 Generated with Claude Code